Self-aligning bearing assembly

ABSTRACT

A self-aligning sleeve bearing assembly including a base member having a surface which includes a socket, a retaining member, and a bearing extending into and from the socket and being sandwiched between the base member and retaining member. The bearing includes two opposing halves which are mismatched along a parting line. The retaining member includes two pairs of independently yieldable opposed fingers which provide four independently operating spring retainers which bear against respective surfaces of the opposing bearing halves and operate together to retain the bearing in place yet allow self-alignment of the bearing.

BACKGROUND OF THE INVENTION

1. Field of the Invention

The present invention relates to a self-aligning bearing assemblyincluding a bearing retainer which changes its form to compensate for abearing having an irregular profile.

2. Description of the Prior Art

The use of self-aligning bearing assemblies is known in the art. Suchassemblies include a support having a recess in which a bearing rests,the bearing being retained in place by a retaining member which engagesthe surface of the bearing to sandwich the bearing between the supportand the retaining member. The retaining member is affixed to the supportto hold the bearing in place relative thereto. Such an assembly is usedto support a rotatable shaft on a fixed structure. Examples of suchself-aligning bearing assemblies are to be found in U.S. Pat. Nos.2,813,762 to Bridenbaugh and 2,938,755 to Lee et al. In these patents, abearing is described having a bore which extends generally perpendicularto the support. A rotatable shaft extends through the bore and throughan opening in the support in such a manner that the shaft is generallyoriented perpendicular to the support.

A somewhat related structure is to be found in U.S. Pat. No. 4,074,158to Cole. This patent describes an electric motor having a motor shaftwhich is supported by self-aligning bearings which are sandwichedbetween retaining members and a portion of the rotor assembly.

In other known similar self-aligning bearing assemblies the bearing iscompletely supported by a retaining member having a plurality of fingerswhich extend therefrom at oppositely and alternately spaced positions toengage the bearing surface. Examples of such self-aligning bearingassemblies are to be found in U.S. Pat. Nos. 1,924,072; 3,701,574; and3,754,802, to Lavigne, Phillips and Keller, respectively.

A somewhat related structure is to be found in U.S. Pat. No. 3,770,990to Winkelmann. This patent describes a bearing structure for a rotatableshaft wherein the assembly includes a splitring bearing. Each section ofthe bearing is retained by a respective retainer ring having a pluralityof circumferentially spaced fingers which extend radially to provide abearing cage for the respective bearing section.

The primary function of a self-aligning bearing assembly is to provideprecise alignment of a rotating shaft relative to the structure to whichit is affixed. It is typical to construct such assemblies usingspherical or partially spherical bearing members or bearing members inthe form of a cylindrical sleeve which have been molded from powderedmetal. For examples, it is known to construct such bearing members fromferrous or non-ferrous materials such as powdered iron, iron-bronze orbronze. In producing such a bearing member by molding, compressed powdermetal is tamped into two mold halves which are closed together in aknown manner. When the bearing member is removed from the mold, there isa tendency for a mismatch to occur at the parting line between opposinghalves of the molded bearing. For example, FIGS. 1 and 2 schematicallydepict a bearing in the form of sleeve bearing 2 which has been moldedfrom powder metal in a known manner, bearing 2 including opposing halves4 and 6. It will be noted that the two halves are offset or mismatchedat the parting line 8. Such a mismatch has an adverse affect upon thecomptability of the bearing with the bearing retainer and base orhousing. In particular, when the bearing is mounted such that the bore10 through which the rotatable shaft 12 extends is horizontal relativeto a supporting surface 14 depicted in phantom lines in FIG. 2, it isdifficult, if possible at all, to use sufficient even pressure to retainthe bearing in place and yet allow the bearing to inherently self-align.

It is highly desirable to provide a self-aligning bearing assemblycapable of functioning in a satisfactory manner notwithstanding that thebearing has been molded from power metal such that there is a mismatchat the parting line between opposing halves of the molded bearing.

It is also desirable to provide a self-aligning bearing assembly andretainer member therefor which compensates for an irregular bearingprofile.

It is further desirable to provide a retaining member, for use in aself-aligning bearing assembly, which retains a bearing having anirregular profile in place using constant pressure and yet allows thebearing to inherently self-align.

SUMMARY OF THE INVENTION

This invention achieves these and other results by providing aself-aligning bearing assembly comprising a bearing having opposinghalves which are mismatched at a parting line. A base member is providedhaving means formed therein for providing a socket into and from whichsuch bearing extends. A retainer is attached to the base member forretaining the bearing in the socket, and to this end the bearing issandwiched between the retainer and the base member. The retainerincluded two pairs of independently yieldable opposed fingers whichprovide four independently operating spring retainers which operatetogether to retain the bearing in place yet allow self-alignment of thebearing. One pair of such fingers is urged against a portion of asurface of one of the opposing halves of the bearing. The other pair ofsuch fingers is urged against a portion of a surface of the otheropposing half of the bearing. The pairs of fingers are spaced from eachother along the parting line.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a perspective view of a molded bearing having two opposinghalves which are mismatched at a parting line;

FIG. 2 is a view of the bearing of FIG. 1 taken along lines 2--2,including a base surface shown in phantom lines;

FIG. 3 is a perspective view of a self-aligning bearing assembly of thepresent invention;

FIG. 4 is a perspective view of one embodiment of the retaining memberof the present invention;

FIG. 5 is a plan view of the assembly of FIG. 3 with the bearing andretaining member having been omitted to simplify the view;

FIG. 6 is a view of FIG. 3 taken along lines 6--6;

FIG. 7 is a view of FIG. 3 taken along lines 7--7;

FIG. 8 is a view of FIG. 3 taken along lines 8--8;

FIG. 9 is a view of FIG. 3 taken along lines 9--9; and,

FIG. 10 is a perspective view of another embodiment of the retainingmember of the present invention.

DESCRIPTION OF THE PREFERRED EMBODIMENT

The embodiment of this invention illustrated in FIGS. 3 to 9 isparticularly suited for achieving the objects of this invention. Inparticular, a self-aligning bearing assembly is depicted comprising abase 20, bearing member 30, and retaining means 50. The base 20 includesan outer surface 22 which includes a socket 24 disposed inwardly fromsurface 22. Socket 24 includes a first surface 26 and a second surface28.

Bearing member 30 extends into and from socket 24. Bearing member 30includes a shaft-receiving bore 32 extending therethrough. Shaft 34extends through bore 32 in a known manner. Shaft-receiving bore 32extends in a first direction along an axis 36 which is coextensive withor parallel to the outer surface 22. In the embodiment depicted in thedrawings, axis 36 is parallel to surface 22. Bearing member 30 includesfirst and second opposing halves 38 and 40, respectively, which aremismatched at a parting line 42 located between halves 38 and 40, theparting line 42 circumscribing axis 36 and lying in a plane 44 whichextends at an angle equal to 90° relative to axis 36. It will be notedthat the shaft receiving bore 32 extends through halves 38 and 40 andthrough the center of the bearing member. As will be explained ingreater detail hereinafter, part of surface 26 engages the firstopposing half 38 of the bearing member and part of surface 28 engagesthe second opposing half 40 of the bearing member.

Retaining means 50 is attached to outer surface 22 as, for example, byscrews 52, for retaining the bearing member 30 in contact with the firstsurface 26 and second surface 28 of socket 24. Retaining means 50includes a first pair 54 of opposing retaining fingers which engage thefirst opposing half 38 of the bearing member (FIG. 7) and a second pair56 of opposing retaining fingers which engage the second opposing half40 of the bearing member (FIG. 6). The first pair 54 and the second pair58 are spaced as at 60 in the direction of axis 36 to provide an openspace at the parting line 42. Such spacing 60 is identified in FIG. 4.

As best depicted in FIGS. 6 and 7, the first and second pair of opposingretaining fingers each includes a first finger 62 and 64 which,respectively, exert first forces against first portions of respective ofthe first and second opposing halves of the bearing member. For example,first finger 62 exerts a force against a first portion 66 of the firstopposing half 38 of the bearing member, and first finger 64 exerts aforce against a first portion 68 of the second opposing half 40 of thebearing member. In a like manner, the first and second pair of opposingretaining fingers each includes a second finger 70 and 72 which,respectively, exert second forces against second portions of respectiveof the first and second opposing halves of the bearing member. Forexample, second finger 70 exerts a force against a second portion 74 ofthe first opposing half 38 of the bearing member, and second finger 72exerts a force against a second portion 76 of the second opposing half40 of the bearing member. The line of action of the force exerted byeach finger extends from the finger through the axis 36 to a respectiveopposing portion of the surfaces 26 and 28. For example, the line ofaction of the force exerted by finger 62 extends from finger 62 throughaxis 36 to an opposing first portion 78 of first surface 26 of socket24, and the line action of the force exerted by finger 64 extends fromfinger 64 through axis 36 to an opposing first portion 80 of secondsurface 28 of socket 24. In a like manner, the line of action of theforce exerted by finger 70 extends from finger 70 through axis 36 to anopposing second portion 82 of first surface 26 of socket 24, and theline of action of the force exerted by finger 72 extends from finger 72through axis 36 to an opposing second portion 84 of second surface 28.Each respective line of action extends through the centerline of thebearing.

The opposing first and second portions 78 and 82 of the first surface 26lie in a first plane 86 and a second plane 88, respectively. In a likemanner, the opposing first and second portions 80 and 84 of the secondsurface 28 lie in a third plane 90 and a fourth plane 92, respectively.Socket 24 comprises the first and second portions of the first andsecond surfaces. By properly orienting surfaces 26 and 28 it is possibleto obtain point contact between the surfaces 26 and 28 and the bearingportion of the bearing member which engages such surfaces. Such pointcontact is obtained by orienting the surfaces such that the first andsecond planes 86, 88 extend downward towards each other from outersurface 22 (FIG. 7), the third and fourth planes 90, 92 extend downwardtowards each other from outer surface 22 (FIG. 6), the first and thirdplanes 86, 90 extend downward towards each other from outer surface 22(FIG. 9), and the second and fourth planes 88, 92 extend downwardtowards each other from outer surface 22 (FIG. 8).

In the retaining means 50, the first and second fingers 62, 70 of thefirst pair 54 of opposing retaining fingers each include a first end 100which are oriented towards and spaced from each other. In a like manner,the first and second fingers 64, 72 of the second pair 56 of opposingretaining fingers each include a first end 102 which are orientedtowards and spaced from each other. Finger 62 and finger 64 each have asecond end 104 each of which is joined to a first mounting flange 106which is attached to outer surface 22 as depicted in FIG. 3. In a likemanner, finger 70 and finger 72 each have a second end 108 each of whichis joined to a second mounting flange 110 which is also attached toouter surface 22 as depicted in FIG. 3. The first mounting flange 106and the second mounting flange 110 are joined by a bridging member 112,the bridging member being spaced from the bearing member in the bearingassembly as depicted in FIGS. 8 and 9.

By providing a self-aligning bearing assembly as described herein havinga retaining means 50 formed from a spring-like material such as springsteel, the fingers of the retaining means impart a retaining force tohold the bearing in place and yet change form to compensate for abearing having an irregular profile to allow selfalignment thereof. Thebridging member 112 is particularly useful in applications where theself-aligning bearing assembly might be subjected to high impact, as forexample, where the assembly is used in a tool such as a drill whichmight be dropped during use. In particular, the bridging member 112allows the spring fingers to stay within their elastic limits so thatthe spring fingers are not overstressed, and movement of the bearing islimited accordingly.

In an alternative embodiment as depicted in FIG. 10 a retaining means120 includes first and second fingers 122, 124 of a first pair ofopposing fingers and first and second fingers 126, 128 of a second pairof opposing fingers. Fingers 122, 124 each include a first end 130 whichare jointed together by a first bridging member 132. In a like manner,fingers 126, 128 each include a first end 134 which are joined togetherby a second bridging member 136. The first bridging member 132 and thesecond bridging member 136 are joined together by a third bridgingmember 138. Bridging members 132, 136 and 138 are spaced from thebearing member shown in phantom lines at 140, and the third bridgingmember 138 extends in the direction of the axis 142 of the shaft bore144. Fingers 122 and 126 each have a second end 146 which are joined toa first mounting flange 148. Similarly, fingers 124 and 128 each have asecond end 150 which are joined to a second mounting flange 152.Mounting flanges 148 and 152 can be attached to the outer surface 22 ofbase 20 in the same manner described regarding retaining means 50.

The embodiments which have been described herein are but some of severalwhich utilize this invention and are set forth here by way ofillustration but not of limitation. It is apparent that many otherembodiments which will be readily apparent to those skilled in the artmay be made without departing materially from the spirit and scope ofthis invention.

I claim:
 1. A self-aligning bearing assembly comprising:a base member; abearing having opposing halves; means formed within said base member forproviding a socket for said bearing, said bearing extending into andfrom said socket; and a retainer having two pairs of independentlyyieldable opposed fingers, one of said pairs engaging a portion of asurface of one of said opposing halves and the other of said pairsengaging a portion of a surface of the other of said opposing halves,said retainer being attached to said base member, said bearing beingsandwiched between said retainer and said base member, and said pairsbeing spaced along said parting line.
 2. A self-aligning bearingassembly comprising a base having an outer surface which includes asocket disposed inwardly from said outer surface, a bearing memberextending into and from said socket, said bearing member having firstand second opposing halves meeting at a parting line located betweensaid hales, said bearing member having a shaft receiving bore extendingthrough said halves, said socket having a first surface, part of whichengages said first opposing half, and a second surface, part of whichengages said second opposing half, and means attached to said outersurface for retaining said bearing member in contact with said first andsecond surfaces of said socket, said retaining means including a firstpair of opposing retaining fingers which engage said first opposing halfof said bearing member and a second pair of opposing retaining fingerswhich engage said second opposing half of said bearing member, saidfirst and second pairs of opposing fingers being spaced to provide anopen space at said parting line.
 3. The self-aligning bearing assemblyof claim 2 wherein said shaft receiving bore extends through the centerof said bearing member in a first direction along an axis coextensivewith or parallel to said outer surface, wherein said parting line liesin a plane which extends at an angle equal to 90° relative to said axis,and wherein said first and second pairs of opposing fingers are spacedin the direction of said axis.
 4. The self-aligning bearing assembly ofclaim 3 wherein said first and second pair of opposing retaining fingerseach includes a first finger which, respectively, exert first forcesagainst first portions of respective of said first and second opposinghalves of said bearing member, the lines of action of said first forcesextending from said first fingers, through said axis, to an opposingfirst portion of said part of respective of said first and secondsurfaces of said socket, and said first and second pair of opposingretaining fingers each includes a second finger which, respectively,exert second forces against second portions of respective of said firstand second opposing halves of said bearing member, the lines of actionof said second forces extending from said second fingers, through saidaxis, to an opposing second portion of said part of respective of saidfirst and second surfaces of said socket.
 5. The self-aligning bearingassembly of claim 4 wherein said opposing first and second portion ofsaid part of said first surface of said socket lie in a first plane anda second plane, respectively, said opposing first and second portion ofsaid part of said second surface of said socket lie in a third plane anda fourth plane, respectively, said socket comprising said first andsecond portions of said part of said first and second surfaces whereinsaid first plane and said second plane extend downward towards eachother from said outer surface, said third plane and said fourth planeextend downward towards each other from said outer surface, said firstplane and said third plane extend downward towards each other from saidouter surface, and said second plane and said fourth plane extenddownward towards each other from said outer surface.
 6. Theself-aligning bearing assembly of claim 4 wherein said first and secondfingers of said first pair of opposing retaining fingers each include afirst end which are joined together by a first bridging member, and saidfirst and second fingers of said second pair of opposing retainingfingers each include a corresponding first end which are joined togetherby a second bridging member.
 7. The self-aligning bearing assembly ofclaim 6 wherein said first and second bridging members are joinedtogether by a third bridging member.
 8. The self-aligning bearingassembly of claim 7 wherein said first, second and third bridgingmembers are spaced from said bearing member, and said third bridgingmember extends in the direction of said axis.
 9. The self-aligningbearing assembly of claim 8 wherein said first finger of said first pairof opposing retaining fingers and said first finger of said second pairof opposing retaining fingers each have a second end which is joined toa first mounting flange which is attached to said outer surface, andsaid second finger of said first pair of opposing retaining fingers andsaid second finger of said second pair of opposing retaining fingerseach have a second end which is joined to a second mounting flange whichis attached to said outer surface.
 10. The self-aligning bearingassembly of claim 4 wherein said first and second fingers of said firstpair of opposing retaining fingers each include a first end which areoriented towards and spaced from each other, and said first and secondfingers of said second pair of opposing retaining fingers each include afirst end which are oriented towards and spaced from each other.
 11. Theself-aligning bearing assembly of claim 10 wherein said first finger ofsaid first pair of opposing retaining fingers and said first finger ofsaid second pair of opposing retaining fingers each have a second endwhich is joined to a first mounting flange which is attached to saidouter surface, and said second finger of said first pair of opposingretaining fingers and said second finger of said second pair of opposingretaining fingers each have a second end which is joined to a secondmounting flange which is attached to said outer surface.
 12. Theself-aligning bearing assembly of claim 10 wherein said first and secondmounting flanges are joined by a bridging member, said bridging memberbeing spaced from said bearing member.